过渡金属氧化物/石墨烯纳米复合材料的快速合成及重金属传感研究

The conductivity and dispersity of transition metal oxide-based material are carefully considered when they are used as an electrochemical sensor for heavy metals. Meanwhile, graphene nanosheet is very easy to agglomerate together and the major of the single-layer graphene is hydrophobic basal carbon, making them showing weak performance on the accumulation of heavy metal ions due to there are lack of active sites on the basal carbon. This project mainly focuses on both the conductivity improvement of metal oxide nanoparticles and the utilization of basal plane of graphene towards heavy metal sensing and then we plan to develop some electrochemical methods for detecting heavy metal ions based on metal oxide/graphene nanocomposite. In this project, we plan to directly decompose metal precursor on graphene surface without any surfactant or binder by using microwave treatment in a minute. As there is the synthesis process is under the high temperature and thus the nanocoposite shows higher stability and homogenous dispersity of metal oxide on graphene surface. By investigating the accumulation ability, sensitivity and selectivity of the metal oxide-graphene composite towards heavy metal ions, we will know the effects of the synthesis process of graphene composite towards the sensor performance, sensitivity and the relative selectivity, indicating the adsorption mechanism and electro transfer process of the heavy metals on the composite surface in molecule level. By this mean we can develop some new materials and methods for heavy metals sensing with high sensitivity and good selectivity, which is expected to provide some clues for the monitoring and removal of toxic heavy metal ions in the environment in both theoretical and experimental ways.

过渡金属氧化物纳米材料作为电化学传感器用于检测和去除环境体系中的剧毒重金属污染物，需要解决导电性和分散性问题；石墨烯虽具有导电性高、比表面积大等优点，然而大部分疏水性基面碳原子因缺乏活性位点而不能有效富集重金属离子，需解决石墨烯的容易团聚和基面碳的充分利用问题。本项目针对上述问题，开展基于过渡金属氧化物/石墨烯复合纳米材料的重金属电化学传感研究。项目拟以过渡金属前驱体和石墨烯混合物为前驱体，利用微波快速加热合成金属氧化物单分散负载石墨烯复合材，通过考察不同粒径分布、不同含量的金属氧化物石墨烯复合材料对重金属离子的富集能力、选择性和稳定性等因素，研究快速微波加热过程对重金属离子的传感性能、灵敏度和选择性等影响，从分子水平上揭示复合材料对重金属离子的吸附机制和电子传递机制，建立高灵敏度、高选择性重金属电化学传感新材料和方法技术，为环境中剧毒重金属离子的检测和污染治理提供新的理论线索和实验依据。

项目针对过渡金属氧化物纳米材料导电性不高、分散性差以及石墨烯等碳材料容易团聚、缺乏活性位点等问题，开展石墨烯等碳基复合纳米材料的重金属电化学传感研究。针对碳材料表面重金属吸附富集位点不多的问题，开发了氮掺杂巴旦木壳多孔碳材料，对铅离子的检测线性范围达到2.0-120 ppb, 检测限为0.7 ppb；以ZIF-8为模板采用静电纺丝法制备了氮掺杂多孔碳纳米纤维材料，对铅和镉离子的检测限分别为0.8 ppb和0.3 ppb；引入硫氰酸作为硫源和氮源可将重金属吸附活性位含量提升至20%以上，传感器对镉离子的线性范围拓宽至2.0-500 ppb；针对金属氧化物导电性不高的问题，在三维细菌纤维素碳上原位生长层状氢氧化铝，利用金属氧化物对重金属离子的良好的吸附富集作用，所制备水合氧化铝-细菌纤维素碳电化学传感器对铅离子和镉离子的线性范围增加至0.5-250 ppb，检测限分别低至0.17 ppb 和0.1 pbb。该项目研究成果为环境中有效态重金属离子原位快速检测分析提供了具有较强应用前景的快速分析方法。